Floor drain traps



United States Patent O 3,335,741 FLOOR DRAIN TRAPS Sven Algot Joel Liljendahl, Gyllenstiernas vag 8, Kallhall, Sweden Filed Nov. 16, 1964, Ser. No. 411,224 Claims priority, application Sweden, Nov. 19, 1963, 12,722/63 4 Claims. (Cl. 137-247.15)

ABSTRACT OF THE DISCLOSURE This invention relates to a iloor drain trap that utilizes an inverted bowl type of valve immediately beneath the drain trap cover to prevent back-llow of water through the trap.

lf conventional iloor drain traps or wells are installed at low levels relatively to the sewer pipe in the street, e.g. are located in cellars, then there is a risk that when the sewer pipe system is overcharged, for instan-ce in consequence of heavy rains, sewer water will tlow backwards up through the trap or well and flood the cellars. In buildings having a sewer pipe system composed by relatively narrow pipes, particularly multi-story houses equipped with sewer pipe risers or trunks of small crosssections, similar risks apply also in respect of wells located in stories above the cellar.` Those risks are due to the pressure rises which may occur in the system upon occasional overcharges thereof, such as if several bath tubs are emptied at the same time. Moreover, according to the conventional design where the 'water emptied from each bathtub passes through an individual iloor well, also when the nominal cross-section of the sewer pipes is of normal size it may occur that, due to the formation of slurries on the inner pipe wall, the effective cross-section is reduced to such `a degree that the outlet water penetrates the apertures of the well strainer ilooding the bath room iloor.

The object of the present invention is to provide a iloor draining trap or well designed in such a way that back-flow of water therethrough is entirely excluded, whereby is eliminated the need of paying attention to the corresponding risk when dimensioning the sewer pipe system within the building and determining the locations of the lloor traps or wells.

According to this invention, a tloor well designed to full the above requirements is mainly characterized therein that said cover is along its periphery sealingly connected to the well, there being below said cover disposed la valve member normally assuming a position spaced from the cover perforations but being arranged to close them when raised under the influence of an upwardly-acting static pressure set up on the rise of the free Water level above a predetermined value.

When the valve member is in its closed position the floor well will form a closed space. This involves that when the water is let out from a bath tub connected to the well there will inside the well be built up a static pressure corresponding to the difference between the free water level in the bath tub and the level inside the well. Under the influence of that static pressure the bath tub is emptied rapidly also in such cases when the pipe connecting the well with the riser is of narrow cross-section and does not slope towards the riser or receiving trunk pipe.

According to a preferred embodiment of the invention said valve member is constituted by a bowl turned upside down and suitably centrally secured to the well strainer cover. It has been found preferable to manufacture the bowl from rubber, synthetic resins or similar materials 3,335,741 Patented Aug. 15, 1967 lCC although it is to be understood that any suitable material could be used. Normally, the bowl assumes a position in which the major portion thereof is spaced from the apertures in the well cover and the rim of the bowl is located somewhat above the water surface. in the well. If that water surface rises, then the air entrapped in the bowl will be compressed so that the bowl bottom is forced into sealing engagement with the well cover. In order to guarantee a complete sealing it is recommendable to provide on the under surface of the well cover a number of annular projections, or ilanges, surrounding the zone in which the cover apertures are located and acting .as valve seats of comparatively small Contact surfaces so that a high contact pressure between them and the valve member is attained.

One embodiment of the invention will now be described in greater detail, reference being made to the accompanying drawing in which:

FIGURE 1 is an elevational cross-sectional view of a lloor draining trap or well designed according to this invention, and

FIGURE 2 shows on a reduced scale the iloor well installed in a bathroom and connected to the outlet pipe from the bath tub.

The iloor well shown in FIGURE 1 does in the conventional manner consist of a comparatively deep bowl 10 which tapers downwards and in which is submerged the downwardly bent portion 11 of a sewer pipe connection 12 so that a drain trap is formed. Normally, the free water surface is at level 13. Reference numeral 14 designates a perforated Well cover or strainer held in position by spring members 1S.

In accordance with this invention a rubber body shaped like a circular bowl 18 turned upside down and having a flexible plane bottom has been secured to the underside of the well cover 14 by means of a bolt 16 and a washer 17. Outside the zone comprising the apertures, or perforations, 19 there project from the lower side cover 14 two concentric annular flanges 26, 21, the bottom surfaces of which are preferably inclined, thereby forming comparatively sharp edges. A sealing ring 22 is disposed between cover 14 and well 10.

If for some reason there would be a back-ilow of Water into the iloor well, e.g. in connection with an overcharge of the sewer system, the water level inside the well will rise. When the free water surface has reached the rim of rubber bowl 18 the air inside the bowl will be entrapped there by the rising water. Upon continued rise of the water level the entrapped air will be compressed, thereby forcing the resiliently flexible bottom of rubber bowl 18 into contact with llanges 20 and 21. vWhen contact has been established the communication between the interior space of the well and the ambient has been effectively interrupted. As is easily understood, this means that the water is prevented from passing through the well cover apertures which would otherwise occur upon further rise of the water level. It is also apparent that a lloor well designed according to the present invention can be installed at low levels relatively to the sewer pipe system in the street, e.g. in cellars, without 'any risk of backll-ow and flooding upon overcharge of the pipe system in consequence of heavy rains.

Turning now to FIGURE 2 the iloor well shown there is mounted in a corresponding recess in the iloor of a bathroom. The well is connected to a vertical riser 23 via a horizontal branch pipe 4 suitably consisting of a plastic tube of comparatively small cross-section.. When the bath tub is emptied the water level inside the well will rise due to the flow resistance offered by the narrow tube 24 so that rubber bowl 18 is brought into engagement with the well cover as above described thus preventing water from ilowing through the perforations therein and ilooding the floor. In the closed space inside the well there will then be built up a relatively great static pressure corresponding to the vertical distance between the free surface in the bath tub and that in the well. Under the influence of that static pressure water will at great speed traverse the narrow pipe 24. Accordingly, a oor well designed according to this invention will exhibit the additional advantage of making its branch pipe selfcleansing.

What I claim is:

1. A floor drain trap comprising:

(a) a collecting bowl,

(b) an inlet to said collecting bowl consisting of a removable perforated cover adapted to be sealingly attached around its periphery to the collecting bowl,

(c) an outlet from said collecting bowl located at some distance above the bottom of the collecting bowl, and

(d) a valve member centrally secured to the underside of said perforated cover,

(1) said valve member comprising a flexible disc that is in the shape of an inverted bowl,

(2) said valve member being adapted to normally assume a sagging position which spaces the valve member away from the cover perforations and wherein its outer lower rim is located above the normal water level in the collecting bowl, whereby an unobstructed passageway is provided between the cover and the bottom of said collecting bowl,

(3) said valve member being adapted to rise t0 a lifted position which obstructs uid flow between the bottom of the bowl and the perforated cover upon the rise of the free fluid level in the collecting bowl.

2. A oor drain trap according to claim 1, wherein said valve member is composed of a material selected from the group consisting of rubber and synthetic resin.

3. A tioor drain trap as set forth in claim 1, wherein the perforated cover has a number of annular anges projecting from the lower side thereof enclosing the zone comprising the perforations and acting as valve seats of comparatively small contact surfaces whereby a high contact pressure between them and said valve member is attained.

4. A floor trap drain comprising:

(a) a collecting bowl,

(b) an inlet to said collecting bowl consisting of a removable perforated cover adapted to be sealingly attached around its periphery to the top of the collecting bowl,

(c) an outlet from said collecting bowl opening located at some distance above the bottom of the collecting bowl, and

(d) a valve member centrally secured to the underside of said perforated cover,

(1) said valve member comprising a shaped exible disc that is concave in a direction away from said perforated cover,

(2) said valve member being adapted to normally assume a sagging position which spaces the valve member away from the cover perforations, whereby an unobstructed uid passageway is provided between the cover and the bottom of said collecting bowl,

(3) said valve member being adapted to rise to a lifted position which obstructs fluid ow between the bottom of the collecting bowl and the perforated cover upon the rise of the free uid level in the -collecting bowl.

References Cited UNITED STATES PATENTS 2,199,675 5/ 1940 Ronning 137-247.15 X 3,267,960 8/1966 Warburton 137--525 X 3,268,018 8/1966 Nielson 137-525 X FOREIGN PATENTS 1,143,456 12/1956 Germany.

37,356 1/ 1936 Netherlands. 128,896 7/ 1950 Sweden.

WILLIAM F. ODEA, Primary Examiner.

D. H. LAMBERT, Assistant Examiner. 

4. A FLOOR TRAP DRAIN COMPRISING: (A) A COLLECTING BOWL, (B) AN INLET TO SAID COLLECTING BOWL CONSISTING OF A REMOVABLE PERFORATED COVER ADAPTED TO BE SEALINGLY ATTACHED AROUND ITS PERIPHERY TO THE TOP OF THE COLLECTING BOWL, (C) AN OUTLET FROM SAID COLLECTING BOWL OPENING LOCATED AT SOME DISTANCE ABOVE THE BOTTOM OF THE COLLECTING BOWL, AND (D) A VALVE MEMBER CENTRALLY SECURED TO THE UNDERSIDE OF SAID PERFORATED COVER, (1) SAID VALVE MEMBER COMPRISING A SHAPED FLEXIBLE DISC THAT IS CONCAVE IN A DIRECTION AWAY FROM SAID PERFORATED COVER, 